Temperature Rising Elution Fractionation (TREF) is an important separation method for characterizing the crystallilinity distribution of polymers (see Wild et al., Polym. Prepr. 18, 182 (1977) and Wild et al., J. Polym. Sci., 20, 441 (1982)). The crystallinity distribution is primarily a function of short chain branching content and controls solid state properties such as density. In general, a nearly linear correlation between elution temperature and short chain branching frequency is observed in an TREF analysis of a semi-crystalline polymer such as “polyethylene” and “polypropylene”.
Gel Permeation Chromatography (GPC) is an important separation method for characterizing the size distribution of polymers. The size distribution of is primarily a function of molecular weight and controls melt properties such as rheology. In general, a logarithmic correlation between molecular weight and elution volume is observed in GPC analysis of a polymer.
Nakano and Goto, J. Appl. Polym. Sci., 24, 4217 (1981) described a TREF/GPC system that provided valuable cross-fractionation characterization of polymer samples. However, the system of Nakano and Goto is not capable of more than one analysis per working day. Therefore, it would be an advance in the art of polymer characterization if a TREF/GPC or GPC/TREF system could be developed that was capable of an increased number of analyses per working day. There is no mention in the prior art of a GPC/TREF system. However, it would be an advance in the art if a system for GPC/TREF were invented.